CN114962508B - A shock-absorbing plate-bar structure with negative Poisson's ratio - Google Patents

Abstract

The invention discloses a shock-absorbing plate-bar structure with a negative Poisson's ratio, which includes a truss and a rhombus rotor. The truss includes periodic units, and the periodic units are nearly concave hexagonal structures. Each group of The nearly concave hexagonal structure of the periodic unit includes a horizontal bar and a diagonal bar. The diagonal bar is symmetrical at both ends of the cross bar and is located on the same side. The cross bar between the diagonal bars on the same side is provided with a rhombus rotor. , the upper and lower sides of the rhombus rotor are provided with trusses, and the two sets of trusses are arranged in parallel, and the trusses and the rhombus rotor are arranged alternately; the plate rod structure of the present invention is loose and porous and has good negative Poisson's ratio performance. Within a certain limit, it can absorb energy when subjected to external vibrations and achieve good shock absorption effect.

Description

A shock-absorbing plate-bar structure with negative Poisson's ratio

Technical field

The present invention relates to the technical field of metamaterials, and in particular to a shock-absorbing plate-bar structure with a negative Poisson's ratio.

Background technique

The Poisson's ratio of materials in nature is mostly positive, showing the phenomenon of shrinkage when stretching or expansion when compressing, while materials with negative Poisson's ratio show the opposite characteristics, that is, the characteristics of tension-expansion and compression-compression. Negative Poisson's ratio materials and structures have great advantages in shear resistance, fracture resistance, energy absorption performance, etc. Metamaterials with negative Poisson's ratio effect usually exhibit lightweight, high damping, sound absorption, and heat insulation. and other physical properties;

Negative Poisson's ratio materials are widely used in aviation, aerospace, medical, electronics and other fields. They are of great significance to the development of aerospace, semiconductor devices, optical components, precision instruments and building materials. Negative Poisson's ratio materials When bent, it expands outward to absorb more energy, thereby absorbing shock and thus playing a protective role;

The current classic negative Poisson's ratio structures are concave polygonal structures, star structures, chiral structures and honeycomb structures. These structures have insufficient performance in terms of inclined rods. At the same time, the vertical rods hinder the movement of the inclined rods to a certain extent, resulting in their rotation ability. Therefore, the present invention proposes a damping plate rod structure with a negative Poisson's ratio to solve the problems existing in the prior art.

Contents of the invention

In view of the above problems, the purpose of the present invention is to propose a damping plate rod structure with a negative Poisson's ratio, which is a plate rod structure with a negative Poisson's ratio.

In order to achieve the purpose of the present invention, the present invention is realized through the following technical solutions: a shock-absorbing plate rod structure with a negative Poisson's ratio, including a truss and a rhombus rotor, the truss including a periodic unit, and the periodic unit is A nearly concave hexagonal structure. The nearly concave hexagonal structure of each group of periodic units includes a horizontal bar and a diagonal bar. The diagonal bar is symmetrical at both ends of the cross bar and is located on the same side. The diagonal bar on the same side is A rhombus-shaped rotor is provided on the crossbar between the rods. Trusses are provided on the upper and lower sides of the rhombus-shaped rotor, and the two sets of trusses are arranged in parallel. The trusses and the rhombus-shaped rotor are arranged alternately.

A further improvement is that the truss and rhombus rotor are made of one of metal, PLA consumables, carbon fiber and composite materials, and are made by 3D printing technology.

A further improvement is that: the distance between the entry point crossbars of the truss on the upper and lower sides of the diamond rotor is 6L, the distance between the far point crossbars is 8L, the length of the upper crossbars of the truss is 6L, and the two groups of The length of the inclined rod is The included angle between the oblique bar and the cross bar is 135°, the side length of the rhombus rotor is 5L, and the included angle at the connection between the hypotenuse of the rhombus rotor and the cross bar is 45°, where L is the size coefficient.

Further improvement is: using Abaqus simulation software to conduct simulation experiments to verify the negative Poisson's ratio lattice model, and perform data processing through the software, and then calculate the Poisson's ratio-time curve after exporting the data.

Further improvements include: using Abaqus simulation software to create a virtual model using SolidWorks before simulating. In the Abaqus simulation software, first set the material parameters, then set the load parameters, compression parameters, divide the finite element mesh, and perform simulation calculations.

The beneficial effects of the present invention are: the plate rod structure of the present invention is loose and porous and has good negative Poisson's ratio performance. Within the elastic limit, it can absorb energy when subjected to external vibration and achieve good shock absorption effect.

Description of the drawings

Figure 1 is a structural diagram showing the distribution structure of the truss and rhombus rotor in Embodiment 1 of the present invention.

Figure 2 is a structural diagram of a periodic unit according to Embodiment 1 of the present invention.

Figure 3 is a graph of true stress and plastic strain curves of AlSi10Mg in Example 2 of the present invention.

Figure 4 is a Poisson's ratio-time curve of the plate-bar structure in Embodiment 2 of the present invention.

Figure 5 is a Poisson's ratio-time curve of the traditional model in Embodiment 2 of the present invention.

Detailed ways

In order to deepen the understanding of the present invention, the present invention will be further described in detail below with reference to examples. This example is only used to explain the present invention and does not constitute a limitation on the protection scope of the present invention.

Example 1

As shown in Figures 1 and 2, this embodiment provides a damping plate rod structure with a negative Poisson's ratio, including a truss and a rhombus rotor. The truss includes periodic units, and the periodic units are nearly Concave hexagonal structure, the nearly concave hexagonal structure of each group of periodic units includes a horizontal bar and a diagonal bar, the diagonal bar is symmetrical at both ends of the cross bar and is located on the same side, and the diagonal bar on the same side A rhombus-shaped rotor is provided on the crossbar between them. Trusses are provided on the upper and lower sides of the rhombus-shaped rotor, and the two sets of trusses are arranged in parallel. The trusses and the rhombus-shaped rotor are arranged alternately.

The truss and rhombus rotor are made of metal, PLA consumables, carbon fiber and composite materials, and are produced through 3D printing technology.

The distance between the entry point crossbars of the truss on the upper and lower sides of the diamond rotor is 6L, the distance between the far point crossbars is 8L, the length of the upper crossbars of the truss is 6L, and the length of the two sets of diagonal bars is The included angle between the oblique bar and the cross bar is 135°, the side length of the rhombus rotor is 5L, and the included angle at the connection between the hypotenuse of the rhombus rotor and the cross bar is 45°, where L is the size coefficient.

Abaqus simulation software was used to conduct simulation experiments to verify the negative Poisson's ratio lattice model, and the software was used for data processing, and the Poisson's ratio-time curve was calculated after exporting the data.

Before using Abaqus simulation software to simulate the simulation, use SolidWorks to establish a virtual model. In the Abaqus simulation software, first set the material parameters, then set the load parameters, compression parameters, divide the finite element mesh, and perform simulation calculations.

Example 2

As shown in Figures 3, 4 and 5, this embodiment provides a simulation verification test of a shock-absorbing plate rod structure with a negative Poisson's ratio, verifies the negative Poisson's ratio lattice model, and performs data processing through the software After processing and exporting the data, calculate the Poisson's ratio-time curve. As shown in Figure 4 of the manual, the minimum Poisson's ratio is -0.849. As shown in Figure 5 of the manual, it is the Poisson's ratio-time curve of the traditional model. The minimum Poisson's ratio is -0.849. The Poisson's ratio is -0.468. After comparison, it is found that the negative Poisson's ratio performance of the designed structure is much better than the traditional negative Poisson's ratio model.

Abaqus simulation software uses SolidWorks to establish a virtual model before simulating. First set the material parameters in Abaqus simulation software, including true stress-true strain parameters, yield strength: 305Mpa, density: 2.7g/cm ³ , elastic modulus: 70GPa, material Poisson's ratio: 0.34. Table 1 below is the true stress and plastic strain table of AlSi10Mg.

Table 1

True stress (MPa) plastic strain True stress (MPa) plastic strain 305 0 409 0.02 337 0.004 424 0.024 357 0.008 438 0.027 377 0.012 452 0.031 393 0.016

Then set the load parameters and compression parameters, divide the finite element mesh, and perform simulation calculations. The experiment simulated the elastic deformation stage under pressure under this model, and the deformation of the material can be observed.

After the simulation is completed, take 6 points on the upper edge surface of the model, and derive the average Y-axis displacement and average Y-axis stress of the 6 points from the Abaqus software; take two points on each side of the middle of the overall model, and derive the average X-axis as above. Displacement, since the model parameters are known, the average X-axis displacement is divided by the total length of the model to obtain the X-axis strain, and the average Y-axis displacement is divided by the total height of the model to obtain the Y-axis strain. Since the simulation experiment applies a certain displacement load and fixed displacement time, so the displacement speed of the press is certain, and there is a one-to-one correspondence between time and displacement, and a Poisson's ratio-time diagram can be drawn.

Negative Poisson's ratio materials are often used in the manufacture of shock-absorbing equipment because of their good ability to absorb energy. However, if the stress exceeds the yield limit of the structure and the model undergoes large plastic deformation, the model is considered to have failed and cannot play its role in reducing vibration. shock effect. Therefore, the following stress is selected to study the Poisson's ratio of the model in the stage before the yield limit.

The basic principles, main features and advantages of the present invention have been shown and described above. Those skilled in the industry should understand that the present invention is not limited by the above embodiments. The above embodiments and descriptions only illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will also have other aspects. Various changes and modifications are possible, which fall within the scope of the claimed invention. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims (9)

1. A shock absorbing plate pole structure with negative poisson's ratio, characterized in that: including truss and rhombus rotator, the truss includes periodic unit, periodic unit is nearly indent hexagon structure, every group periodic unit's nearly indent hexagon structure contains horizontal pole and diagonal bar, diagonal bar symmetry is at horizontal pole both ends and be located the homonymy, homonymy be equipped with the rhombus rotator on the horizontal pole between the diagonal bar, the rhombus rotator upside all is equipped with truss and two sets of truss parallel arrangement, truss and rhombus rotator alternate arrangement setting.

2. The shock absorbing panel rod structure with negative poisson's ratio according to claim 1, wherein: the truss and diamond rotator manufacturing material is one of metal, PLA consumable, carbon fiber and composite material.

3. The shock absorbing panel rod structure with negative poisson's ratio according to claim 1, wherein: the distance between the truss inlet cross bars at the upper side and the lower side of the diamond-shaped rotator is 6L, and L is a size coefficient.

4. The shock absorbing panel rod structure with negative poisson's ratio according to claim 1, wherein: the distance between the cross bars at the far point is 8L, and L is the size coefficient.

5. The shock absorbing panel rod structure with negative poisson's ratio according to claim 1, wherein: the length of the truss upper cross bar is 6L, and L is a dimension coefficient.

6. The shock absorbing panel rod structure with negative poisson's ratio according to claim 1, wherein: the lengths of the two groups of diagonal rods are ∈2L, and L is a size coefficient.

7. The shock absorbing panel rod structure with negative poisson's ratio according to claim 1, wherein: the included angle between the inclined rod and the cross rod is 135 degrees.

8. The shock absorbing panel rod structure with negative poisson's ratio according to claim 1, wherein: the side length of the diamond-shaped rotator is 5L, and L is a size coefficient.

9. The shock absorbing panel rod structure with negative poisson's ratio according to claim 1, wherein: the included angle between the oblique side of the diamond-shaped rotary sub-and the joint of the cross bar is 45 degrees.